Base station apparatus based on switch fabric in broadband wireless communication system

ABSTRACT

A base station (BS) apparatus in a broadband wireless communication system is provided. The base station apparatus includes at least one function board for processing a baseband digital signal; at least one processor board for controlling the at least one function board; and at least one switch for routing a signal between the at least one function board and the at least one processor board.

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY

This application claims priority under 35 U.S.C. §119(a) to anapplication filed in the Korean Intellectual Property Office on Jan. 9,2007 and assigned Serial No. 2007-0002344, the disclosure of which isherein incorporated by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to a structure of a base station(BS) in a broadband wireless communication system, and in particular, toa BS apparatus with an easily extended structure in the broadbandwireless communication system.

BACKGROUND OF THE INVENTION

In a broadband wireless communication system, a base station (BS)apparatus is a system component responsible for communications with aterminal through a radio channel and is a very central device in termsof the radio channel and the access management of the terminal in thewireless communication system.

The data rate required in fourth (4G) generation communication systems,which are the next-generation communication systems, will increasingfrom units of hundreds of Kbps to several Gbps. To respond to this, thebase station is evolving into a structure capable of rapidly processinga number of digital data. In addition, chip sets including FieldProgrammable Gate Arrays (FPGAs), digital signal processors (DSPs), andhigh-speed processors, are advancing to process at the required digitaldata rates. However, since a single chip set is not able to satisfy thecapacity required for new base stations, the structure of the basestation is advancing to combine a plurality of chip sets.

FIG. 1 depicts a conventional base station (BS) structure in a broadbandwireless communication system.

The base station of FIG. 1 can be divided largely into a digitalprocessor and a radio frequency (RF) processor. The digital processorincludes a backplane 110, a processor board 120, a channel card 130, andan intermediate frequency (IF) board 140. The RF processor includes asignal transceiver 150.

The backplane 110 provides signal paths among the components in thedigital processor; that is, among the processor board 120, the channelcard 130, and the IF board 140. The backplane 110 is of a fixedstructure at the design phase of the base station. The structure of thebackplane 110 limits the number of the processor boards 120, the channelcards 130, and the IF boards 140 connectable in the base station. Thatis, the backplane 110 determines the hardware structure of the basestation.

The processor board 120 controls functions of the base station. Forexample, the processor board 120 processes interfacing with an externaldevice and provides a digital signal fed from an upper layer to thechannel card 130 to send the digital signal to a corresponding terminal.

The channel card 130 includes a processor 131, a DSP 133, and an FPGA135. The channel card 130 performs encoding and decoding and modulatingand demodulating; that is, functions as a modem. The processor 131controls functions of the channel card 130. The DSP 133 and the FPGA 135can be separate physical components but can be considered as the samefunctional component in the implementation. In some cases, the channelcard 130 may include only one of the DSP 133 and the FPGA 135.

The IF board 140 converts the digital signal fed from the channel card130 to an analog signal of the IF band and provides the analog signal tothe signal transceiver 150, and converts an analog signal fed from thesignal transceiver 150 to a digital signal and provides the digitalsignal to the channel card 130. The signal transceiver 150 converts andamplifies the signal fed from the IF board 140 to an RF signal and sendsthe RF signal over an antenna. The signal transceiver 150 amplifies andconverts a signal received on the antenna to an IF signal and providesthe IF signal to the IF board 140.

As mentioned above in FIG. 1, the digital processor of the base stationis constituted on the board basis to execute the respective functionsand the boards exchange the signals via the backplane. Herein, thebackplane is formed as the fixed structure at the system design phase.Thus, to install more channel cards over the limited number to increasethe processing capacity of the base station, it is necessary to design anew backplane. The channel card can be physically divided into the DSP,the FPGA, and the processor as shown in FIG. 1. When those chips arenewly developed, it is required to re-configure the channel card.Besides, as the shape of the channel card changes, the interface alsochanges. In this situation, the alternation of the whole base station(BS) structure including the backplane may be inevitable. Namely, theconventional BS structure is vulnerable to the shape alternation causedby those reasons.

SUMMARY OF THE INVENTION

To address the above-discussed deficiencies of the prior art, it is aprimary aspect of the present invention to substantially solve at leastthe above problems and/or disadvantages and to provide at least theadvantages below. Accordingly, an aspect of the present invention is toprovide a base station (BS) apparatus for facilitating the addition ofchannel cards to extend a capacity in a broadband wireless communicationsystem.

Another aspect of the present invention is to provide a base stationapparatus for facilitating the shape alternation in a broadband wirelesscommunication system.

The above aspects are achieved by providing a base station apparatus ina broadband wireless communication system. The base station apparatusincludes at least one function board for processing a baseband digitalsignal; at least one processor board for controlling the at least onefunction board; and at least one switch for routing a signal between theat least one function board and the at least one processor board.

Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, itmay be advantageous to set forth definitions of certain words andphrases-used throughout this patent document: the terms “include” and“comprise,” as well as derivatives thereof, mean inclusion withoutlimitation; the term “or,” is inclusive, meaning and/or; the phrases“associated with” and “associated therewith,” as well as derivativesthereof, may mean to include, be included within, interconnect with,contain, be contained within, connect to or with, couple to or with, becommunicable with, cooperate with, interleave, juxtapose, be proximateto, be bound to or with, have, have a property of, or the like; and theterm “controller” means any device, system or part thereof that controlsat least one operation, such a device may be implemented in hardware,firmware or software, or some combination of at least two of the same.It should be noted that the functionality associated with any particularcontroller may be centralized or distributed, whether locally orremotely. Definitions for certain words and phrases are providedthroughout this patent document, those of ordinary skill in the artshould understand that in many, if not most instances, such definitionsapply to prior, as well as future uses of such defined words andphrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 depicts a conventional BS structure in a broadband wirelesscommunication system; and

FIG. 2 depicts a BS structure in a broadband wireless communicationsystem according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2, discussed below, and the various embodiments used to describethe principles of the present disclosure in this patent document are byway of illustration only and should not be construed in any way to limitthe scope of the disclosure. Those skilled in the art will understandthat the principles of the present disclosure may be implemented in anysuitably arranged wireless communication system.

The present invention provides a base station (BS) structure forfacilitating a capacity extension in a broadband wireless communicationsystem.

FIG. 2 depicts a base station (BS) structure in a broadband wirelesscommunication system according to an embodiment of the presentinvention.

The base station of FIG. 2 can be divided largely into a digitalprocessor and a radio frequency (RF) processor. The digital processorincludes switches 210-1 through 210-(k+N), a switch controller 220,processor boards 230-1 through 230-N, Field Programmable Gate Array(FPGA) boards 240-1 through 240-N, digital signal processor (DSP) boards250-1 through 250-N, and intermediate frequency (IF) boards 260-1through 260-N. The RF processor includes signal transceivers 270-1through 270-N.

The switches 210-1 through 210-(k+N) provide signal exchange paths amongthe function boards in the digital processor. For example, the switches210-1 through 210-(k+N) can be constituted using a plurality ofelectrical switches or a plurality of optical switch fabrics. Theswitches 210-1 through 210-(k+N) can provide N×M or M×M ports and freelyinterconnect the function boards connected to the ports. Compared to theconventional apparatus of FIG. 1, the switches 210-1 through 210-(k+N)function as the backplane of FIG. 1. However, contrary to the fixedstructure of the backplane 110, the switches 210-1 through 210-(k+N) canbe extended according to a designer's intention by freelyinterconnecting the ports. With the extendable structure, the switches210-1 through 210-(k+N) are not subject to the limitation on the numberof the connectable function boards.

The switch controller 220 controls the routing of the ports of theswitches 210-1 through 210-(k+N). More specifically, for the propersignal exchange among the function boards connected to N×M or M×M portsof the switches 210-1 through 210-(k+N), the switch controller 220controls the routing between the ports of the switches 210-1 through210-(k+N) of the base station.

The processor boards 230-1 through 230-N execute the functions of thebase station. The processor boards 230-1 through 230-N execute thefunctions of the processor 131 of the channel card 130 of FIG. 1, aswell as the interface processing function with the external device ofthe processor board 120. Since the channel cards are separated on thechip basis and constituted as the individual function boards in the basestation of the present invention, the processor boards 230-1 through230-N control modem functions of the FPGA boards 240-1 through 240-N andthe DSP boards 250-1 through 250-N. In some cases, at least one of theprocessor boards 230-1 through 230-N control the routing of the ports ofthe switches 210-1 through 210-(k+N).

The FPGA boards 240-1 through 240-N and the DSP boards 250-1 through250-N are the function boards including FPGA chips or DSP chips whichcarry out encoding and decoding and modulating and demodulating ofinformation bit strings (i.e., modem functions). The FPGA boards 240-1through 240-N and the DSP boards 250-1 through 250-N are classifiedbased on whether the physical form of the embedded chip is the FPGA orthe DSP. In the implementation, the FPGA boards 240-1 through 240-N andthe DSP boards 250-1 through 250-N can be classified to the same boardin terms of the function. Accordingly, the base station may include onlyone of the FPGA boards 240-1 through 240-N or the DSP boards 250-1through 250-N.

The IF boards 260-1 through 260-N receive the digital signals from theFPGA boards 240-1 through 240-N or the DSP boards 250-1 through 250-Nvia the switches 210-1 through 210-(k+N), convert the digital signals toanalog signals of the IF band, and output the analog signals to thesignal transceivers 270-1 through 270-N. The IF boards 260-1 through260-N convert analog signals fed from the signal transceivers 270-1through 270-N to digital signals and provide the digital signals to theFPGA boards 240-1 through 240-N or the DSP boards 250-1 through 250-N.

The signal transceivers 270-1 through 270-N convert and amplify thesignals fed from the IF boards 260-1 through 260-N to RF signals andtransmit the RF signals over the antennas. The signal transceivers 270-1through 270-N amplify and convert signals received on the antenna to IFsignals and provide the IF signals to the IF boards 260-1 through 260-N.

When the switches 210-1 through 210-(k+N) are implemented using opticalswitch fabrics, every function board in the digital processor; that is,the processor boards 230-1 through 230-N, the FPGA boards 240-1 through240-N, the DSP boards 250-1 through 250-N, and the IF boards 260-1through 260-N include optical interface devices (not shown). Using theoptical interface, the speed of the optical signals transmitted betweenthe function boards can be 1.25 Gbps, 2.5 Gbps, and 10 Gbps. Also, usingthe optical interface, the optical signals can be transmitted andreceived by varying their wavelength on the board basis.

In FIG. 2, all of the processor boards 230-1 through 230-N are connectedto the switch 210-1. For ease of explanation, the boards are arranged bydiscriminating or ordering them based on their type. In other words, theprocessor boards 230-1 through 230-N may be connected to any switchbesides the switch 210-1 and the switch 210-1 has the same structure andfunction as the other switches.

As set forth above, by constituting the digital processor of the BSbased on the extendable N×M or M×M switches in the broadband wirelesscommunication system, function boards can be easily added to increasethe capacity of the BS. When the switch is implemented using the opticalswitch, the design can be free from the channel capacity interference,Electro Magnetic Interference (EMI)/Electro Magnetic Compatibility(EMC), and the rapid signal transmission among the function board arefeasible. Further, it is easy to increase the capacity and the RFantennas of the BS system to which Smart Antenna (SA) and Multiple InputMultiple Output (MIMO) techniques are applied. The present invention isapplicable to next-generation wireless communication systems requiringthe capacity over 1 Gbps and the MIMO antenna.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

1. A base station apparatus in a broadband wireless communicationsystem, the apparatus comprising: at least one function board configuredto process a baseband digital signal; at least one processor boardconfigured to control the at least one function board; at least oneintermediate frequency (IF) board configured to receive digital signalsfrom the at least one function board, convert the digital signals toanalog signals, and transmit the analog signals to a signal transceiver;and at least one switch configured to perform a function of a backplaneand provide at least one adjustable and extendable signal path among theat least one function board and the at least one processor board, the atleast one switch further configured to selectively couple the at leastone function board and the at least one IF board, wherein a number ofports to connect the at least one function board and the at least oneprocessor board are increased by adding a new switch to the at least oneswitch.
 2. The base station apparatus of claim 1, wherein the at leastone function board comprises at least one of a digital signal processor(DSP) chip and a field programmable gate array (FPGA) chip.
 3. The basestation apparatus of claim 1, wherein the at least one switch comprisesat least one electrical switch.
 4. The base station apparatus of claim1, wherein the at least one switch comprises an optical switch fabric.5. The base station apparatus of claim 4, wherein the at least oneprocessor board is connected to the at least one switch using an opticalinterface.
 6. The base station apparatus of claim 4, wherein the atleast one function board is connected to the at least one switch usingan optical interface.
 7. The base station apparatus of claim 1, furthercomprising: a controller configured to control the routing of the atleast one switch.
 8. The base station apparatus of claim 1, wherein theat least one processor board is further configured to control therouting of the at least one switch.
 9. A wireless network comprising aplurality of base stations operable to communicate with mobile stationsin a coverage area of the wireless network, wherein each of the basestations comprises: at least one function board configured to process abaseband digital signal; at least one processor board configured tocontrol the at least one function board; at least one intermediatefrequency (IF) board configured to receive digital signals from the atleast one function board, convert the digital signals to analog signals,and transmit the analog signals to a signal transceiver; and at leastone switch configured to perform a function of a backplane and provideat least one adjustable and extendable signal path among the at leastone function board and the at least one processor board, the at leastone switch further configured to selectively couple the at least onefunction board and the at least one IF board, wherein a number of portsto connect the at least one function board and the at least oneprocessor board are increased by adding a new switch to the at least oneswitch.
 10. The wireless network of claim 9, wherein the at least onefunction board comprises at least one of a digital signal processor chipand a field programmable gate array chip.
 11. The wireless network ofclaim 9, wherein the at least one switch comprises at least oneelectrical switch.
 12. The wireless network of claim 9, wherein the atleast one switch comprises an optical switch fabric.
 13. The wirelessnetwork of claim 12, wherein the at least one processor board isconnected to the at least one switch using an optical interface.
 14. Thewireless network of claim 12, wherein the at least one function board isconnected to the at least one switch using an optical interface.
 15. Thewireless network of claim 9, further comprising: a controller configuredto control the routing of the at least one switch.
 16. The wirelessnetwork of claim 9, wherein the at least one processor board is furtherconfigured to control the routing of the at least one switch.
 17. Adigital processor apparatus of a base station, the digital processorapparatus comprising: a plurality of function boards configured toprocess a baseband digital signal; a set of processor boards configuredto control the plurality of function boards; a plurality of intermediatefrequency (IF) boards configured to receive digital signals from thefunction boards, convert the digital signals to analog signals, andtransmit the analog signals to one or more signal transceivers; and aset of switches configured to perform as a backplane of the digitalprocessor apparatus and route signals among the plurality of functionboards and between at least one of the set of processor boards and atleast one of the plurality of function boards, the set of switchesfurther configured to selectively couple the function boards and the IFboards.
 18. The digital processor apparatus of claim 17, wherein theplurality of function boards comprises at least one of a plurality ofdigital signal processor (DSP) chips and a plurality of fieldprogrammable gate array (FPGA) chips.
 19. The digital processorapparatus of claim 17, wherein the set of switches comprises at leastone of a set of electrical switches and an optical switch fabric. 20.The digital processor apparatus of claim 17, further comprising: aswitch controller configured to control the routing of the set ofswitches.